Safety container for explosive fluids



Dec. 5, 1967 .J SZEGO 3,356,256

SAFETY CONTAINER FOR EXPLOSIVE FLUIDS Filed Oct. 25, 1965 2 Sheets-5heet1 IN VE N TOP.

74 JOSEPH SZEGO.

F/G 5 by Z m.

Agent.

Dec. 5, 1967 J. SZEGO 3,356,256

SAFETY CONTAINER FOR EXPLOSIVE FLUIDS Filed Oct. 23, 1965 2 Sheets-Sheet2 INVENTOR JOSEPH 52560.

Agen

United States Patent Ofiice 3,356,256 Patented Dec. 5, 1967 3,356,256SAFETY CONTAINER FOR EXPLOSIVE FLUIDS Joseph Szego, 27 Kenwood Ave.,Toronto; Ontario, Canada Filed Oct. 23, 1965, Ser. No. 503,754 16Claims. (Cl. 220-88) ABSTRACT OF THE DISCLOSURE A container having afiller therein formed of thin netting in the form of thinintegrally-connected, heat-conductive ribbons which are deformed toimpart stiffness and crush resistance to the netting.

The present invention relates to fluid containers, particularly tocontainers for inflammable and/or explosive fluids; the term fluidsbeing deemed to cover both liquids and gases.

In the past various safety measures have been adopted to prevent fireand explosions in such containers and these have mainly, if not always,included the provision of a heat conducting filler for the container.The object of such a filler was, of course, to disperse localconcentrations of heat throughout the entire filler as well as throughthe body of the container, and thus prevent the formation of hot-spotscapable of igniting the fluid contents of the container.

One type of filler is that disclosed in Canadian Patent No. 652,316 inwhich I am named as co-inventor, and consists wholly of metal wool, thefluid contents of the container being accommodated in the interstices ofthe wool. This type of filler has not proved wholly satisfactory becausealthough when the filler was first inserted in the container it mighthave occupied substantially the Whole thereof, it tended to becomedisplaced and compressed by the action of the liquid in the container toan extent whereby it was squeezed into one corner of the container, forexample, leaving whole regions of the container completely unprotectedby the filler.

Other types of known filler have also suffered from the same orcorresponding disadvantages which need not be enumerated in detailherein.

It is a broad general object of the present invention to provide animproved heat dispersing filler for the interior of a container forinflammable fluids which is of high thermal conductivity, light inweight and economical to produce.

It is a further object of the invention to provide an improved filler asaforesaid which is durable and resistant to corrosion by the fluids towhich it is exposed in normal use.

It is a further object of the invention to provide an improved filler asaforesaid which is of high thermal conductivity, light in weight andeconomical to produce and is yet sufliciently stifi" or rigid stronglyto resist crushing or compression within the container by the agitationof liquid therein.

It is a further object of the invention to provide an improved fillercomprised of normally pliable, light-Weight material of high thermalconductivity reinforced to provide a relatively stiff or rigid fillerstructure resistant to the deforming action of liquid within thecontainer.

It is a further object of the invention to provide an improved filler asaforesaid which has a very small displacement in relation to the volumeof the container whereby substantially the whole of the container may becharged with fluid, but which yet has sufficient bulk to occupy thewhole of said container and procure wide and rapid dispersion of heatapplied to the exterior of the container to prevent ignition of thecontainer contents.

It is a further object of the invention to provide an improved filler asaforesaid including a plurality of filler units, each unit beingcomposed of several layers of netting; some of said layers having higherthermal conductivity than others and some of said layers having greatercrush resistance than others.

It is a further object of the invention to provide an improved filler asaforesaid which permits free flow of fluid in every directiontherethrough and also allows levelling of fluid in the container toavoid obstructing filling and emptying of said container and the freeflow of liquid therein.

It is a further object to provide an improved filler as aforesaid havingsuflicient rigidity to support itself within a container.

It is a still further object of the invention to provide a fluidcontainer including an improved filler as aforesaid.

It is also an object of the invention to provide a method ofsafeguarding a container for explosive fluids against the effects ofheat applied externally thereto.

The foregoing objects are achieved in accordance with the invention bythe provision of a fluid container comprising an outer shell enclosing afluid chamber and a filler occupying substantially the whole of saidchamber. The filler is composed, for at least the major part, of aspecies of netting made up of interconnected metallic ribbons whosewidths are misaligned with, and preferably perpendicular to, the generalplane of the netting thereby stiffening the netting. The netting as awhole is relatively thin permitting free flow and levelling of fluidswithin the chamber whereby filling and emptying of the container is notappreciably impeded.

Other features, objects, and advantages of the invention will beapparent from the ensuing illustrative description of one preferredembodiment thereof when read in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a portable gasoline can in accordancewith the invention, certain portions of the can being broken away toreveal otherwise concealed internal detail;

FIG. 2 is a fragmentary plan view of a layer of coarse mesh netting ascontemplated by the invention superimposed upon a fine mesh nettinglayer;

FIG. 3 is an enlarged isometric view of a fragment of metallic netting;

FIG. 4 is a side elevation of the netting of FIG. 3 seen in thedirection of the arrow IV of that figure;

FIG. 5 is an end elevation of the netting of FIG. 3 seen in thedirection of the arrow V of that figure;

'FIG. 6 is an isometric view generally corresponding to FIG. 3 butshowing a different type of netting;

FIG. 7 is a fragmentary isometric view of a filler unit in accordancewith the invention;

FIG. 8 is a view generally corresponding to FIG. 7 but showing anotherform of filler unit, and

FIG. 9 is a much enlarged isometric view of a small portion of thenetting shown in FIG. 3.

A container 2 in accordance with the invention is shown in FIG. 1. Forthe purposes of illustration the container 2 is shown as a portablegasoline can including an outer shell 4 which defines a fluid chamber 6wherein the fluid contents of the can are held.

The container 2 in accordance with conventional practice also includesinlet and outlet facilities for the chamber 6, said facilities in thepresent instance consisting of a simple spout 8 which functions as bothinlet and outlet for the chamber 6.

In accordance with the invention the chamber 6 contains a filler 10which occupies substantially the whole of said chamber. It should benoted that the invention is principally directed to the combination ofthe container and the tiller, although invention is also believed toreside in the filler itself and the ensuing description thereforerelates to both these aspects of the invention.

As has already been hereinbefore stated a most obvious desideratum in acontainer as herein visualized is, of course that it be maximallythermoconductive to dissipate heat concentrations and to avoid ordissipate hot spots which might otherwise conduce to ignition ofinflammable fluids contained therein.

This desideratum is achieved by installing in the interior of thecontainer a filler providing numerous interlaced conductors by which aconcentration of heat at any one spot is expeditiously disseminatedthroughout the filler to the farthest extremities of the container andso rendered harmless.

However, it is also of very great importance that the filler diminishthe capacity of the container by the smallest possible extent and add aslittle as possible to the weight thereof.

It also need hardly be stated that a most efficient filler isnecessarily one which does not impede the free movement of liquid fuelsin the container.

An important component of a filler which is believed to serve theobjects of the invention most effectively makes liberal use of netting12 composed of integrally connected ribbons 14 of thin, relativelymalleable metal which is, of course, thermoconductive andnon-inflammable. Various types of netting 12 are shown in FIGS. 2-6 and9. The netting itself is relatively thin-that is to say its dimensionperpendicular to its plane P is smail and may be arranged in layers and/or convolutions and/ or other dispositions within the chamber 6 as willbe described in greater detail hereinafter.

For convenience the netting 12 has been shown more or less symbolicallyin FIG. 1, the structure thereof being better shown in the enlargedscale views of FIGS. 3 and 9. To form the netting 12 the ribbons 14 maybe interconnected and merge with each other at spaced points along theiredges, an indicated at in FIG. 3.

It is noteworthy, however, that the ribbons 14 are so arranged in thenetting 12 that their widths W (or their own planes) are misaligned withthe general plane P of the netting. In FIGS. 4 and 9, for instance, itwill be seen that the widths W of the ribbons are substantiallyperpendicular to the plane P, while in FIG. 6 the ribbons 14 are twistedto misalign their widths W with the plane P. In either case it may besaid that the planes of the ribbons 14 are disposed at a substantialangle to the plane P. The misalignment has the effect of stiffening thenetting 12 to resist bending forces acting generally perpendicularly tothe plane P.

As mentioned above the ribbons 14 are formed of thin relativelymalleable metal and may be readily bendable about axes parallel to thedirection of their widths W. It will be appreciated, however, that theribbons 14 are much more strongly resistant to bending about axesparallel to the direction of their thickness and that the netting 12being composed of ribbons 14 with their widths misaligned with the planeP of the netting, is thereby stiffened as aforesaid. Since it isenvisaged that the directions of the thickness of the ribbons 14 and ofthe thickness of the netting 12 as a whole will be more or lessperpendicular to each other, to avoid confusion it should be explainedthat the thickness of the ribbons is the dimension sometimes referred toin the case of sheet metal as the gauge.

As noted above the primary function of the filler 10 is to dissipateheat concentrations and accordingly the netting 12 is required to fillthe chamber 6 as completely as possible to achieve maximal heatdispersal. Conversely the primary function of the container 2 is to holdfluid and it is highly desirable that the filler 10 should have aminimal displacement and weight so that the fluid capacity of thechamber 6 is not seriously reduced and the overall weight of thecontainer 2 and its contents is not appreciably increased.

The netting 12 has been found highly satisfactory from this point ofview since it is possible to achieve an effective filling of the chamber6 by using said netting in quantities with a displacement equivalent tobetween one and three percent of the volume of the chamber 6, a typicalfiller 10 having a displacement equivalent to approximately two percentof the volume of chamber 6.

For the sake of absolute clarity it should be explained that theexpressions filler, fill and filling as used herein in connection withthe netting 12 indicate only that the netting as a whole constitutes orforms the major part of a bulky unit which extends over substantiallythe full length, breadth and height of the chamber 6, although asindicated above the actual displacement of such unit may be as little asone percent of the volume of the chamber 6. It will be obvious that thisbulk/displacement ratio is achieved by reason mainly of the large numberof open interstices 16 in the netting 12 which communicates with eachother, as will be explained in more detail hereinafter, and form, as itwere, cells in which the fluid contents of the container 2 arereceivable.

The ribbons 14 may be of aluminum and in any event should be resistantto corrosion by the fluids to which they will be exposed in use.

As an example, netting 12 as contemplated by the invention may be formedof aluminum ribbons inch wide and .006 inch thick, the meshes of thenetting having a dimension of approximately A inch in the direction ofthe plane P of the netting. Thus, dimensioned, it will be seen that thevarious thicknesses of netting 12 offer very little if any impedance tothe movement of liquid in the container.

The efficiency of the invention may be further assessed from thefollowing exemplary data.

The coefficient of thermal conductivity of aluminum at 300 C. is .64c.g.s. units.

To fill a container of 1 cubic metre (or 1,000,000 cubic centimetres)capacity with netting of the above dimensions the actual weight ofnetting recommended would be approximately 52.4 kilogrammes, while thedisplacement of this weight of netting would be 19,370 cubiccentimetres, which is, of course, 1.937% of the total capacity of thecontainer.

This quantity of netting when spread out in a fiat state would cover aplane area of 354.8 square metres and may be rolled, folded or otherwiselayered to make a filler for filling the space of one cubic metre withinthe container.

354.8 square metres of netting with the above mentioned coefficient ofthermal conductivity are capable of conducting 1060 million calories perhour or about 300,000 calories per second.

The container in question may be an aircraft fuel tank, or part thereof,containing gasoline. In typical crash conditions, said container maybecome fractured and permit leakage of gasoline therefrom; this being afairly common condition. The gasoline leaking from the tank may thenignite creating a source of intense heat about the fractured tank. Theignition temperature of gasoline is about 280 C. and when burning freelythe flames may not be expected to exceed this temperature.

It will thus be seen that by conducting heat away from the fracture atthe rate of about 300,000 calories per second, the filler 10 of theinvention would be more than adequate to prevent the internaltemperature of the tank from attaining the ignition temperature of itscontents.

Ribbons formed of anodized aluminum have been found somewhat strongerand, in some applications, more corrosion resistant than those ofnon-anodized aluminum, and certain alloys, such as aluminum alloyed withberyllium and/or titanium, have also been found suitable for thepurposes of the invention.

The foregoing data is given for purposes of illustration only and itshould be understood that netting with larger or smaller interstices andformed of ribbons of other material having other widths and thicknessesmay be used. The invention contemplates, in fact, that under certainconditions the filler may comprise netting 12 of different mesh sizesand different thicknesses. Thus, for example, a filler formation may beemployed wherein layers of relatively fine but weak mesh netting havinghigher conductivity are interposed between layers of relatively coarsemesh netting; the ribbons in the fine mesh netting being preferablythinner (of smaller gauge) and narrower than those of the coarse meshnetting. The terms fine and coarse indicate that the interstices of thenetting are respectively small and large.

This construction is illustrated in FIG. 7 which shows a convolutedfiller unit 10a wherein a web of coarse mesh netting and two webs offine mesh netting are wound together so that the resulting unitcomprises a plurality of layers 12a of coarse mesh netting between eachpair of which'are disposed two layers 12b of fine mesh netting. For thesake of clear exposition a small air space has been shown between theseveral layers, although in practice the respective layers 12a and 12bof the unit are more or less contiguous with the layers adjacentthereto. The interstices 16 of each layer are out of registration withthe corresponding interstices of adjacent layers whereby each intersticeconstitutes, as it were, a fluid cell communicating with other fluidcells. The latter feature is best illustrated in FIG. 2 which shows, inplan, a portion of a layer 12a superimposed upon a portion of a singlelayer 12!).

It will be appreciated that fluid can circulate within the filler unit19a not only through the interstices 16, but also, to some extent,between the layers 12a and 12b, and that it is free to circulate in alldirections and rapidly levels itself within the container 2, thisfeature being due to the fact that the netting 12 does not include anysingle element of substantial area which could form a dam and obstructthe free flow offiuid within the container. The container 2 is shown ina tilted condition in FIG. 1 and the level of gasoline therein 'isindicated by the broken line 18.

The filler 10 may be composed of or include one or more units Ilia. Ineither case the fine mesh netting, which, although stiffened by thedisposition of its component ribbons as previously described, may yet berelatively flexible in comparison with the coarse mesh netting, servesto disperse and dissipate heat more rapidly than the coarse meshnetting, whereas the coarse mesh netting is stiffer than and reinforcesthe fine mesh netting against crushing and compression within thechamber 6 such as may be caused by movement of fluid within a partlyfilled container. That is to say if a container 2 contains a quantity offluid short of its total capacity, said fluid will tend to swill aboutwithin the container when the latter is agitated and such movement maystress the filler 10 and exert compressive forces thereon. It will beclear that if the filler 10 is crushed or compressed to any substantialextent, leaving voids unoccupied by the filler material, the degree ofthe protection afforded by the filler 10 will be correspondingly reducedsince heat applied to the exterior of the container 2 in a regionadjacent such a void will not be disseminated through the filler 10 inthe manner visualized by the invention and could cause an explosion.

It is contemplated that the netting 12 as a whole (i.e. in FIG. 7 thecombination of layers 12a and 12b) will be sufliciently stiff or rigidto support itself within the chamber 6, although additionalreinforcements may be. added if desired.

The netting 12 may, of course, be arranged in other Ways, one possiblealternative arrangement being illustrated in FIG. 8 which shows a fillerunit 10b. As shown the unit 16b includes a layer 120 of stiff coarsemesh netting which is corrugated to enhance its stiffness still 6further. Layers 12d of relatively flexible fine mesh netting aredisposed on each side thereof, the whole being fastened together as bywire (not shown) to form a laminar structure.

A plurality of units 1012 may be used to form a complete filler 10, orone or more units 10b may be assembled with one or more units 10a orother filler units to make up a complete filler.

For example the filler 10 of FIG. 1 is shown as including a filler unit10b disposed horizontally in the lower part of chamber 6, a plurality offiller units 10a disposed horizontally in the middle part of the chamber6 and a filler unit 100, which may consist entirely of convoluted finemesh netting, horizontally disposed at the top of the chamber 6. It willbe apparent that the filler unit is positioned where it will be leastexposed to compressive forces but where it protects a space whichbecomes filled with an explosive mixture of gasoline and air as gasolineis poured from the container 2, and where rapid dissipation of heatconcentrations is particularly important.

Also shown in FIG. 1 is a plug 26 filling the container spout 8. Theplug 20 is composed of netting 12 and may be a narrow strip of suchnetting rolled into cylindrical form as shown. The inner end of the plug20 may contact one or more of the filler units in the chamber 6 and itwill be understood that the plug permits free flow of fluid through thespout 8 during filling or emptying of the container 2.

Although the invention has been described with particular reference to aportable gasoline can, its application is not, of course, restrictedthereto. Other exemplary applications are the fuel tanks of landvehicles and aircraft and containers for inflammable gases.

By way of resume it may be said that the invention provides an explosioninhibiting filler for the interior of a container for inflammable fluidscomprising a netting ofintegrally connected, thermoconductive ribbons.Each ribbon is composed of thin, relatively malleable,corrosion-resisting metal such as the alloys previously mentioned. Thedisposition of the ribbons within the netting is arranged to enhance thestiffness of the netting as a whole, this being achieved by misaligningthe widths of the ribbons relative to the general plane of the netting..Conversely the netting structure is such as to permit free flow andcirculation of fluid within the container without giving rise toundesirable damming effects.

Many changes and modifications in the exemplary embodiment of theinvention described herein will be obvious to a person skilled in theart to which this invention relates and it will be understood that theinvention comprehends all such changes and modifications as fall withinthe scope of the claims now following.

What I claim is:

1. A container for fluids comprising,

an outer shell enclosing a fluid chamber;

means communicating between the exterior and interior of the chamberproviding it with inlet and outlet facilities;

a filler occupying substantially the whole of said chamber, and nettingarranged in layers and constituted by integrallyconnected,thermo-conductive, non-inflammable ribbons forming a major part, atleast, of said filler;

said ribbons being composed of thin metal which is malleable andrelatively wide in relation to its thickness and said ribbons havingtheir width misaligned with the general plane of said netting impartingstiffness to the latter;

the respective layers of netting being relatively thin permitting freeflow of fluids therebetween conducing to relatively unimpeded levelingof the fluid within said chamber.

2. A container as claimed in Claim 1 wherein:

said ribbons have their widths disposed substantially perpendicular tothe general plane of said netting.

3. A container as claimed in claim 1 wherein:

the layers of netting are convoluted within said chamber.

4. A container as claimed in claim 1 wherein:

said netting is formed of anodized aluminum.

5. A container as claimed in claim 1 wherein:

said netting is formed of an alloy of aluminum, beryllium and titanium.

6. A container as claimed in claim 1 wherein:

said layers are contiguous;

each said layer including meshes disposed out of registration withcorresponding meshes of adjacent layers permitting free circulation offluid in all directions within said chamber 7. A container as claimed inclaim 1 wherein:

said layers are contiguous;

some of said layers comprising relatively fine mesh netting wherein thegauge of said ribbons is relatively low providing a relatively high rateof heat dispersal therefrom and others of said layers comprisingrelatively coarse mesh netting wherein the gauge of said ribbons isrelatively high providing rigidity for said coarse mesh layers andreinforcing said fine mesh layers to enhance the rigidity and crushresistance of said filler as a whole.

8. A container as claimed in claim 7 wherein:

the gauge of said ribbons comprising said coarse mesh netting is such asto render said netting self-supporting within said chamber and to resistcrushing of said netting by the movement of liquids within said chamber.

9. An explosion-inhibiting filler for the interior of a container forinflammable fluids comprising:

netting arranged in layers and constituted by integrally-connected,thermo-conductive, non-inflammable ribbons;

said ribbons being composed of thin metal which is malleable andrelatively wide in relation to its thickness and said ribbons havingtheir widths misaligned with the general plane of said netting impartingstiffness to the latter;

the respective layers of netting being relatively thin permitting freeflow of fluids therebetween.

10. A filler as claimed in claim 9 wherein:

said ribbons have their widths disposed substantially perpendicular tothe general plane of said netting.

11. A filler as claimed in claim 9 wherein:

said layers are contiguous;

some of said layers comprising relatively fine mesh netting wherein thegauge of said ribbons is relatively low providing a relatively high rateof heat dispersal therefrom and others of said layers comprisingrelatively coarse mesh netting wherein the gauge of said ribbons isrelatively high providing rigidity for said coarse mesh layers andreinforcing said fine mesh layers to enhance the rigidity and crushresistance of said filler as a whole.

12. A filler as claimed in claim 11 wherein:

said coarse mesh layers are corrugated reinforcing said fine mesh layersand further enhancing the rigidity and crush resistance of the filler asa Whole.

13. A filler as claimed in claim 9 wherein:

said netting is formed of anodized aluminum.

14. A filler as claimed in claim 9 wherein:

said netting is formed of an alloy of aluminum, beryllium and titanium.

15. A filler as claimed in claim 9 wherein:

said netting includes relatively flexible fine mesh netting andrelatively stifl coarse mesh netting;

said fine and coarse mesh netting being convoluted together procuringreinforcement of the fine mesh netting by the coarse mesh netting.

16. A filler as claimed in claim 9 wherein:

said layers are contiguous;

each said layer including meshes disposed out of registration withcorresponding meshes of adjacent layers permitting free circulation offluid in all directions between said layers.

References Cited UNITED STATES PATENTS 958,944 5/1910 Steward 220881,693,958 12/1928 Patten 22088 2,850,083 9/1958 Frost 22088 3,069,04212/1962 Johnston 22010 FOREIGN PATENTS 652,316 11/1962 Canada.

705,745 3/ 1965 Canada.

601,374 11/ 1925 France.

329,822 11/ 1920 Germany.

531,610 l/1941 Great Britain.

RAPHAEL H. SCHWARTZ, Primary Examiner.

1. A CONTAINER FOR FLUIDS COMPRISING, AN OUTER SHELL ENCLOSING A FLUIDCHAMBER; MEANS COMMUNICATING BETWEEN THE EXTERIOR AND INTERIOR OF THECHAMBER PROVIDING IT WITH INLET AND OUTLET FACILITIES; A FILLEROCCUPYING SUBSTANTIALLY THE WHOLE OF SAID CHAMBER, AND NETTING ARRANGEDIN LAYERS AND CONSTITUTED BY INTEGRALLYCONNECTED, THERMO-CONDUCTIVE,NON-INFLAMMABLE RIBBONS FORMING A MAJOR PART, AT LEAST, OF SAID FILLER;SAID RIBBONS BEING COMPOSED OF THIN METAL WHICH IS MALLEABLE ANDRELATIVELY WIDE IN RELATION TO ITS THICK-